Stress suppresses our response to cancer treatment

Researchers from The University of Queensland (UQ) have shown that chronic stress dampens the immune system’s response to cancer, reducing the effectiveness of immunotherapy treatments.

Writing in the journal Cancer Immunology Research, Dr Stephen Mattarollo and his colleagues revealed how they induced stress pathways in mouse models of lymphoma to reflect chronic psychological stress. The lymphoma progressed much faster than if these pathways weren’t triggered, according to Dr Mattarollo, and when immunotherapies were used on the mice they were not able to respond as effectively as those which had not been stressed.

“This is because the stress led to poor function against the cancer by T-cells, which are very important in the immune system’s control and surveillance of tumours and are a major target in many immunotherapy treatments,” Dr Mattarollo explained.

“Many conventional therapies such as chemotherapy also rely on components of the immune system for their effectiveness.”

The researchers recognise that increased anxiety comes naturally with a cancer diagnosis, with stress levels highly likely to increase regardless of a patient’s baseline level. The key, therefore, is to manage this stress in order to ensure the best possible outcome for patients.

“If we can manage stress or have lifestyle interventions which manage stress, particularly for cancer patients through their journey, it’ll help not only with how they’re feeling, but also in their ability to respond to these type of therapies,” Dr Mattarollo said.

The researchers are additionally looking into medically ‘blocking off’ stress pathways in cancer patients, seeking to combine immunotherapy treatments with commonly used blood pressure drugs that block the effects of stress hormones.

“We hope this will reduce the stress-induced neural signalling and improve immune function,” Dr Mattarollo said.

“We are about to test this combination in animal models.”

PhD candidate Michael Nissen, a co-author on the study, added that as immunotherapies become more widely available, it is important to build up a comprehensive list of factors which influence their effectiveness.

“The more we know, the better chance we have of designing them effectively and efficiently to work in cancer patients,” Nissen said.